Fig. 1

Study design. Syrian golden hamsters, male, 8 weeks old, were exposed to 7,12-dimethylbenz[a]anthracene (DMBA) three times a week. At hyperplasia, dysplasia, or papilloma stage, animals were randomized among experimental groups and received intracardially vehicle or 0.7 × 10⁶, 7 × 10⁶, or 21 × 10⁶ mesenchymal stem cells (MSCs)/kg. Every week, buccal pouches were assessed macroscopically. At the end of study period (13 weeks), tumors were analyzed microscopically. For each stage, homing of donor cells into precancerous lesions was evaluated 1 day after MSC administration